Method for cleaning metering lines in automatically controlled laundry care devices, in which flowable laundry treatment agents are added in automatically metered doses from at least one reservoir via a metering line to a laundry treatment process, it being possible, after adding a dose, to flush said metering line by means of a rinsing agent, in particular by means of water.
Such methods are used in appliances and/or washing machines of the prior art (DE 32 37 785 A1, DE 35 25 365 A1, EP-421 085 A2). Water is regularly used here as a rinsing agent, namely fresh water directly from the mains water supply in DE 32 37 785 A1, fresh water from a water supply, which as is known exists in the detergent supply duct and is used to seal against clouds of vapor developing from the tub (DE 35 25 365 A19) and fresh water from the mains water supply, which is stored in an expendable quantity in a reservoir (EP-421 085 A2). All known techniques of flushing metering lines are used to prevent detergents and washing agents (bleaching agents, softeners) from mixing, as a result of which reactions between different laundry treatment agents may arise. There is a risk of long-chain molecules or water-insoluble connections undesirably developing, or exothermic reactions or damage to individual laundry items occurring. To avoid such dangers, those line areas, which are wet by a respectively metered laundry treatment agent and are subsequently referred to as a metering line, are flushed with said rinsing agent (water, especially fresh water) after its addition.
It is however common to all known measures for flushing the metering line that after flushing, residues of the mixture of fresh water and small proportions of the already flushed laundry treatment agent remain behind. Particularly with the use of organic chemicals (e.g. detergent tensides), this can result in a massively increased potential of germ formation. Correspondingly by contrast, highly concentrated tenside solutions, which, where possible, are even adjusted in terms of alkali, have biocidal properties. Residues of such solutions cannot therefore develop germs.
On the other hand, the portions of washing agent in the remaining residues of rinsing solutions may result in the surface drying, sedimentations or incrustations on delivery facilities (pumps, valves) and may as a result cause interferences in its operation.